A large percentage of motor vehicles currently in use in the United States have combustion engine exhaust gas systems that include catalytic converters. The catalytic process for the conversion of undesired constituents in the exhaust gases which is provided by the catalytic converter often requires the injection of secondary air into the exhaust gas. In maintaining or replacing the catalytic converter part of the exhaust system it may be necessary to use an auxiliary air injection means to supply such air to the exhaust gas.